Rust inhibiting composition



Patented Sept. 1 6, 1952 RUST INHIBITING COMPOSITION Milton P. Kleinho'lz, East Chicago, 1nd,, assignor" I a to Sinclair Refining Company, New York; N. Y.,

a corporation of Maine No Drawing. Application June 8, 1946,

, Serial No. 675,443

My invention relates to compositions whichin contact with metals prevent or retard the corrosion thereof. The compositions are especially suitable for preventing the rusting of iron and steel surfaces but may be employed to inhibit the corrosion, due to water or moisture, of nonferrous metals including copper, brass,-bronze, zinc, aluminum, magnesium alloys, and bearing metals, such as copper-lead alloys, nickel alloys, sulfur-nickel alloys, etc.

Some of my compositions may be used as lubricating or hydraulic oils, or, depending upon the concentration of active ingredients, may be added to such oils in such amounts as to impart their corrosion-inhibiting properties thereto; others are particularly valuable for use, in lieu of the usually-employed slushing oils and other protectorants, in the preservation, for example. of idle machinery, storage drums, castings, tools, spare parts, etc.

A composition according to my invention is prepared by compounding with a mineral oil, such as a petroleum oil, or with a mineral wax or jelly, such as paraffin wax or petrolatum, calcium mahogany sulphonate and alpha-hydroxylauric acid or the product resulting upon the partial self-esterification of such acid.

Calcium mahogany sulfonate is produced by the neutralization with lime of sludger'frea sulfuric acid-treated petroleum oil and isthus' distinguished from calcium green acid sulfonate obtained by reaction of acid sludge with lime. It is my usual practice to employ the calcium mahogany sulfonatein the form of a concentrate in the oilifrom which it was derived.

As between the unesterified acid and the partially self-esterifled acid, I prefer the latter because it affords somewhat better'resultsa The esterification of alpha-hydroxylauric acid pro ceeds with the formation of lactide-type compounds as illustrated by the following equations in which R=CH122 RCHOHCOOH+BCHOHOOOH Ron-coon:

0=c1cn0H -R I Seml-lactide ncnonooon+ncnoncoon R-CH-CO pc':'cn-a Lactlde In preparing the esterified material for use in the practice of my invention, it is advantageous to 4' Claims. (Gl.106--14) inthe'lactide. The reaction is easily efiected by heating the acid at a temperature of the order of 200-250 F., most suitably in the presence of a solvent, such as toluene, while providing for the removal of the water oflreaction.

For best results, I have found that the concentration of the 'sulphonate in the mineral oil or wax base should at least slightly exceed the concentration of the acid orpartially esterified acid. The total concentration ofthe two "components is determined by practical considerations- Thus, I may prepareoil concentrates for shipping purposes, suitable ior subsequent dilution with additionalquantities of oil, having much higher concentrations of the addends than are necessary for adequate protection of the particular metal surfaces to be protected. The maximumtotal concentrationoi these concentrates is determined only by the solubility of the co-acting materials in the particular oil being employed.

I have determined that, in general, excellent protection is obtained with a sulphonate concentration of from 1-2% on the total Weight of the composition and an acid or partially esterified acid concentration on the same basis of from 0.54%. My compositions as prepared for use, therefore, generally contain the sulphonate and acid or esterified acid in such concentrations.

Treatment of a :metalsurface with a composition prepared according to my invention may involve a single or intermittently repeated contact of the surface with the composition or the composition may be maintained in a continuous contact with the surface. Where the composition is applied as a protective coating to articles such as tools, castings, and the like, the method of application is determined by the particular. circumstances including the equipment available. In some instances, treatment may be by dipping or immersion, while in other instances, it may be considered most advantageous to spray or brush the surface with the composition. When prepared as a material which is solid at ordinary temperatures, the corrosion-inhibiting composition may in some cases be melted before use, while in other cases it may be applied in the manner of a wax.

. My invention is further illustrated by the following examples, which show, inter alia, that my additives co- -act in a synergistic manner, the total efiect being much greater than the sum of the two effects taken independently. In thetest referred to in Examples 1-5, two steel panels measuring about 2 x 3".x A3" are sand-blasted to give a fresh metal surface. They are then dipped in the material under test for one minute,

3 drained 4 hours, and placed in a cabinet maintained at 100% humidity at 120 F. At 24 or 48 hour periods, the panels are inspected for rust spots or areas.

The calcium mahogany sulfonate employed in the exeriments on which the examples are based was prepared by treatment of a 200 viscosity midcontinent neutral oil with fuming sulfuric acid,

followed by separation of the resulting sludge and reaction of the mahogany acids in the acid 011 with lime. The resultant oil after steam .reduction to bottoms contained about 25% of calcium mahogany sulfonate and tested as follows:

4 Example 2 0.5 part of partially self-esterified alpha-hydroxylauric acid was blended with 99.5 parts of the base oil. Panels dipped in this blend and placed in the humidity cabinet rusted in 24 hours. Increasing the amount ,of the additive to 1% increased the humidity cabinet life to 96 hours.

, Example 3 0.5 part of unesterifled alpha-hydroxylauric acid wasmixed with 99.5 parts of the base oil The alpha-hydroxylauric acid used in the ex-; periments was prepared in the following manner: 2790 grams (10 moles) of crude alpha-bromolauric acid and a solutionv of 1680 grams ('30 moles) of potassium hydroxide in 6.7 liters of water were introduced into a '5 gallon Pfaudler kettle. Upon heating to reflux, the organicphase dissolved completely. The solution was reacted at reflux for about 8 hours. It was then acidified with 3 liters of concentrated hydrochloric acid, with prolonged stirring. The aqueous phase was then drawn off at about 170 F. The crude alphahydroxylauric acid was given a second acid wash,

followed by two water washes at about 190 R, at which temperature the organic acid is molten and more readily handled. The crude, wet, molten acid obtained analyzed 200 acid number, 0.2% bromine and 0.06% sulfate ash. It weighed 2637 grams, and soon solidified.

In the preparation of the partially self -esterified alpha-hydroxylauric acid tested according to the examples, 2570 grams of the'crude alphahydroxylauric acid was heated'in an open flask over an 8 hour period, the course of the reaction being followed by acid numbers run on hourly samples. The acid number at the endof the 8 hour period was 174 as against 215 after 3 hours heating. The product was an orange-brown oil which solidified at room temperature.

The base oil in the case of Examples 1 to 5 was a solvent extracted Mid-Continent SAE aircraft oil of the following characteristics:

Gravity, API 25.8 Flash point, "P p 550 Fire point, F 625 Vis. SSU 1751.8 Vis. SSU 680.4 Vis. 210 SSU .122 Pour point, F +5 Color NPA 0+ ASTM ash, per cent 0.00 Carbon residue, per cent i 0.36

heated at 1. Although the acid at the stated temperature appeared to dissolve in the oil, it precipitated upon cooling to room temperature.

A subsequently prepared mixture containing 0.5 part of alpha-hydroxylauric acid, 5 parts of the sulfonate concentrate and 94.5 parts of the base oil .remained clear on standing and protected steel panels against rusting in the humidity cabinet for about 300 hours. i

- Example 4 One part of alpha-hydroxylauric acid, 5 parts oi th'e sulfonate concentrate and 94 parts of the base oil were mixed and the blend tested bythe humidity cabinet procedure.- One panel had a cabinet life of 312 hours, the other a life of .408 hours.

Example 5 One part of partially self-esterifled alphahydroxylauric acid, 5 parts of the 'sulfonate concentrate and 94 parts of the base oil were mixed and tested by the usual procedure. One panel had a life of 528 hours,-the other a life of 408 hours. Increasing the quantity of sulfonate concentrate to 7.5 parts and decreasing'the amount of base oil commensurately to 91.5 parts did not increase the humidity cabinet life. 1

Example 6 Gravity, API 19.8 Flash point, F. 465

Vis.210 SSU c 75.2 Acid N0. 1.5 Melting point, F -157.8 Calcium,-per cent .073 Sulfur, per cent 0.34

Duplicate steel panels of thesame measurements as the panels of thepreceding examples, after sand-blasting, were dipped in the blend which had been heated to 180 F., and allowed to drain overnight. They were then suspended at an angle of 45 to the earths surface'on an unshaded southern exposure. No {rust had formed after 30 days. i v a T I The'East Texas neutral extract'and the petrolatum employed in the preparation of the blend had the following properties:

MeltingPoint "F Neutral Potrola- Extract tum Gravity APL. 33.3 Fl sh Point "F 555 Fire Point F. 630 Vis.100SSU Vis. 210 SSU... 79.8 Acid No 0.0 Seponification No 0'84 Example 7 The test of Example 6 was repeated with the same result using a blend containing 71 parts of the petrolatum, 23 parts of the neutral extract, 5 parts of the sulfonate concentrate and 1 part of partially self-esterified alpha-hydroxylauric acid.

The properties of this blend were as follows:

Gravity, API 20.8 Flash point, F. 485 Vis. 210 SSU 74.9 Acid No. 1.1 Melting point, F. 156.8 Calcium, per cent .073 Sulfur, per cent 0.33

Example 8 The test of Example 6 was repeated with the same result using a blend containing 71 parts of the petrolatum, 20.5 parts of the neutral extract, 7.5 parts of the sulfonate concentrate and 1 part of partially self-esterified alpha-hydroxylauric acid.

The properties of this blend were as follows:

Gravity, API 20.5 Flash point, F. 470 Vis. 210 SSU 78.1 Acid No. 1.0 Melting point, F. 157.0 Calcium, per cent 0.111 .Sulfur, per cent 0.33

Earample 9 The test of Example 6 was repeated with the same result using a blend containing 71 parts of the petrolatum, 20.5 parts of the neutral extract, 7.5 parts of the sulfonate concentrate and 1 part of unesterified alpha-hydroxylauric acid.

The properties of this blend were as follows:

Gravity, API 20.8 Flash point, F. 475 Vis. 210 SSU 75.8. Acid No. 1.3 Melting point, F. 156.0 Calcium, per cent 0.112 Sulfur, per cent 0.36

Example 10 may be present in the oil a viscosity index iniprover, for example, or a dye to improve the color, or an oxidation inhibitor, or a foam suppress-or or all of these. Since calcium sulfonate is an efiective detergent, it is usually unnecessary to add a detergent as a separate item when compounding a crank case or other oil to specifications demanding the presence of a detergent.

I claim:

l. A composition adapted to inhibit the rusting of iron and steel consisting essentially of a mineral oil as its base and about 1-2% calcium mahogany sulfonate and about 0.5-1% of a material of the group consisting of alpha-hydroxy lauric acid and the product resulting upon partial self-esterification of such acid and which contains in admixture the acid, the semi-lactide esterification product of the acid, and a relatively minor proportion of the lactide esterification product of the acid.

2. A composition adapted to inhibit the rusting of iron and steel consisting essentially of a base substance from the group consisting of mineral oils and waxes and jellies derived therefrom and about 12% of calcium mahogany sulf-onate and about 0.5-1% of alpha-hydroxy lauric acid.

3. A composition adapted to inhibit the rusting of iron and steel consisting essentially of abase substance from the group consisting of mineral oils and waxes and jellies derived therefrom and about 1-2% of calcium mahogany sulfonate and about '0.5-1% of the product resulting upon partial self-esterification oi alpha-hydroxy lauric acid and which contains in admixture the acid, the semi-lactide esterification product of the acid, and a relatively minor proportion of the lactide esterification product of the acid.

4. A composition according to claim 3 where v the partial self-esterification product is that which predominates in the compound formed upon condensation of two molecules of alphahydroxy lauric acid with the elimination f one molecule of water.

- MILTON P. KLEINHOLZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date I 2,182,992 Lebo Dec. 12, 1939 2,281,676 Cook May 5, 1942 2,334,158 Fuchs et al. Nov. 9, 1943 2,348,715 Adams May 16, 1944 2,383,033 Adams et al Aug. 21, 1945 2,398,193 Sharp Apr. 9, 1946 2,403,928 Kleinholz July 16, 1946 

1. A COMPOSITION ADAPTED TO INHIBIT THE RUSTING OF IRON AND STEEL CONSISTING ESSENTIALLY OF A MINERAL OIL AS ITS BASE AND ABOUT 1-2% CALCIUM MAHOGANY SULFONATE AND ABOUT 0.5-1% OF A MATERIAL OF THE GROUP CONSISTING OF ALPHA-HYDROXY LAURIC ACID AND THE PRODUCT RESULTING UPON PARTIAL SELF-ESTERIFICATION OF SUCH ACID AND WHICH CONTAINS IN ADMIXTURE THE ACID, THE SEMI-LACTIDE ESTERIFICATION PRODUCT OF THE ACID, AND A RELATIVELY MINOR PROPORTION OF THE LACTIDE ESTERIFICATION PRODUCT OF THE ACID. 